Activity measurements for thulium (Tm) 170

["Monty Charles" <charlemw@novell1.bham.ac.uk>]

Does anyone have any experience of measuring the activity of thulium 
(Tm) 170?  We are using the 84 keV gamma line and an abundance of 
3.2% (Lederer) to evaluate the activity of small (hot particle) 
sources. We have some indications from associated measurements of 
the beta spectrum and dose measurements that the activity may be low 
by up to 50%.  Can anyone advise us on the accuracy of the abundance 
values given in the literature regarding low energy gamma/X-rays from 
thulium 170?
Dr Monty Charles, Reader in Radiation Physics
School of Physics & Space Research
University of Birmingham
Edgbaston
Birmingham B15 2TT
England
TEL +44  0121 414 3483
FAX +44  0121 414 4725
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